voltage test main board (LAQ55C) 30-inch

Hi, I would like to check if the main power board is ok or not. You can find some checks about 24.5 V and so but not clearly how to do it. Is there a clear test point for the board of a 30-inch Cinema Display? tests of the other boards (inverter and video) also welcome! SO to be clear, I want to know where to measure with a multimeter and which information this gives

and with this info how to repair the board(s)